1. Field
The following description relates to a system and method for skeletal muscle stimulation.
2. Description of Related Art
Sarcopenia is the degenerative loss of muscle mass due to aging. This disease is commonly seen in the elderly, and about 40% of people over the age of 65 are afflicted by this disease. When muscle mass is reduced by sarcopenia or other muscle degenerative diseases, basal metabolism typically decreases. A person with decreased basal metabolism typically gains weight easily and becomes susceptible to chronic diseases such as hypertension, and the like. When a muscle of the lower body is weakened by a loss of muscle mass, an everyday activity such as walking may be made difficult, and a person typically becomes more vulnerable to injuries related to the weakened muscular abilities. For example, injuries related to falling while walking may become more frequent.
A muscle has a combination of slow twitch muscle fibers and fast twitch muscle fibers. Slow twitch muscle fibers are characterized by high endurance and slow contraction speeds. For example, slow twitch muscle fibers are typically more common in muscles of marathon athletes. Fast twitch muscle fibers have faster contraction speeds and are typically used during high agility exercises. For example, fast twitch muscle fibers are used for everyday activities such as lifting an object. Activities such as lifting an object typically require an application of an instant high intensity force. Dynamic activities of the slow twitch muscle fibers and the fast twitch muscle fibers are most frequently found in people in their twenties.
However, as humans age, the slow twitch muscle fibers and the fast twitch muscle fibers gradually start to degenerate. Slow twitch muscle fibers exhibit a gradual atrophy whereas atrophy of fast twitch muscle fibers is much less gradual. For example, slow twitch muscle fibers may be maintained in people having seventy years of age in order to facilitate walking for long periods of time. On the other hand, statistics have found that all fast twitch muscle fibers may degenerate at once when humans enter their thirties.
One way of suppressing atrophy of fast twitch muscle fibers and reduction in muscle mass is through routine and frequent exercise. However, studies have shown that finding sufficient time for routine exercise is difficult. Accordingly, routine exercise is typically not a feasible model for suppressing muscle atrophy.